Evidence-based guidelines for asthma management have been available to practicing physicians since 1991.1 Randomized controlled clinical trials have demonstrated that implementation of asthma guideline recommendations can significantly improve patient- level outcomes in asthmatics of all ages. However, in primary care practices, adoption and implementation of guideline recommendations continues to be inconsistent and uneven. Implementation of guidelines is challenging. Simple strategies like clinician education and toolkits alone are usually insufficient. Significant widespread and long- lasting improvements will require generalizable interventions that increase motivation and capacity for change and focus on changing processes of care. These interventions must be feasible and acceptable to primary care practices. Interventions like practice facilitation (PF), which add to rather than deplete practice resources, and local learning collaboratives (LLC), which produce competition and collaboration between practices have shown promise but require further study. We propose to conduct a 2 x 2 factorial (four-arm), mixed-method, cluster randomized controlled trial (RCT) of PF and LLC, provided individually and in combination, compared to provision of the asthma guidelines and a toolkit plus performance feedback (GTF) alone, to test the effectiveness and acceptability of these interventions for implementation of the most recent National Heart Lung and Blood Institute-endorsed asthma guideline in primary care practices. The specific aims are: Aim 1 (System-Level Effects): Evaluate the impacts of the proposed interventions -- GTF, PF, LLC, and the combination of PF and LLC -- on three key components of practice change, priority for the specific changes, change process capability (capacity to change), and care process content (the specific changes in process required for guideline implementation);Aim 2 (Guideline-Level Effects): Compare the effectiveness of four implementation interventions -- A) GTF, B) GTF plus PF, C) GTF plus LLC, and D) GTF, PF, and LLC -- on the practices'implementation of the six key messages of the NHLBI asthma guidelines;and Aim 3 (Moderators): Test the relationships between key practice characteristics -- use of electronic health records (Y/N), presence of mid-level clinicians (Y/N), practice ownership (clinicians own Y/N), and number of clinicians in the practice (#) -- guideline implementation. PUBLIC HEALTH RELEVANCE: Statement of Relevance If evidence-based guidelines for asthma management were implemented in primary care practices throughout the United States, we could reduce outpatient and emergency room visits by 56% and 91% respectively. This project will provide valuable information that will allow us to evaluate the effectiveness of four practice change strategies to improve asthma guideline implementation in primary care practices. If effective, the same strategies could be used to facilitate implementation of other chronic disease guidelines.